Spring starter motor



April 7, 1964 Filed June 5, 1961 F/Gl.

A. w. SPARROW SPRING STARTER MOTOR lTIT' M; MW-1,; W,

3 Sheets-Sheet 1 Inventor ALA/V. WyCL/FFE SPARROW By fim April 7, 1964 w, SPARROW 3,127,883

SPRING STARTER MOTOR Filed June 5, 1961 5 Sheets-Sheet 2 ,"U IVI 7.5 x m 45 44 43 38 Inventor ALA/V WYCL/FFE SPARROW y %t%s April 7, 1964 A. w. SPARROW 3,127,883

SPRING STARTER MOTOR Filed June 5, 1961 5 Sheets-Sheet 3 FIGS.

Inventor ALAN WYCL/F/ f SPARROW M22, Jaw/#4;

/ A itormy United States Patent 3,127,883 SPRHNG- STARTER MOTOR Alan Wycliffe parrow, Peterborough, England, assignor to F. Perkins Limited, London, England, a British company Fiied June 5, 1961, Ser. No. 114,825 Claims priority, appiieation Great Britain June 9, 1960 7 Claims. (Cl. 123-179) The present invention relates generally to motors for starting interial combustion engines, and more specifically concerns a spring starter motor particularly useful for relatively small engines suitable for marine use.

It is the primary aim of the invention to provide an improved spring starter motor that is eflicient and safe. More specifically, it is an object of the invention to provide an improved starter motor which cannot be accidentally tripped When wound and which has no projecting parts which are driven during the starting operation.

Another object is to provide an efficient starter motor as described above which is quite compact while being capable of exerting engine-starting torque over an appreciable interval so as to insure reliable starting. A more detailed object is to provide a starter motor of the above type utilizing a plurality of series coupled, spirally wound springs connected in a compact arrangement which minimizes internal friction.

A further object is to provide a spring starter motor of the above character in which the spring power unit can be easily removed as a distinct cartridge for assembly, replacement or servicing with no special tools or procedures being required.

Still another object is to provide a starter motor having the above advantages and features which is quite economical to manufacture.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:

FIGURE 1 is a longitudinal section of a starter motor constructed in accordance with the invention;

FIG. 2 is a section taken approximately along the line II-II in FIG. 1;

FIG. 3 is a fragmentary section taken approximately along the line IIIIII in FIG. 2;

FIG. 4 is a side elevation of a single helically wound part embodied in the motor shown in FIG. 1;

FIG. 5 is a plan view of the part shown in FIG. 4 before being wound into helical form; and

FIGS. 6 to 9 are somewhat diagrammatic, stop-motion views illustrating operation of the structure shown in FIG. 2.

While the invention will be described in connection with a preferred embodiment, it will be understood that I do not intend to limit the invention to that embodiment. On the contrary, I intend to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. 7

Turning now to the drawings, the starter of FIG. 1 includes a cylindrical frame 1 containing a rotatable and axially shiftable shaft 2 and a spring power unit 3 mounted on the shaft 2. The spring power unit 3 includes a plurality of pairs of spiral springs and, in the illustrated embodiment, four springs 4, 5, 6 and 7 are arranged in pairs, with springs 4 and 5 being one pair and springs 6 and 7 being the other pair. The springs are connected in series in the manner described below and it will be apparent that any number of spring pairs can be provided depending upon the desired operating characteristics of the starter. The springs 4-7 form the energy storage portion of the starter and in the preferred construction are fitted within the ice frame 1 and on the shaft 2 as a unitary cartridge which can be readily handled as a single assembly.

The frame 1 consists of a rear end casting 8 adapted to be bolted to the body of the internal combustion engine to be started, a front end casting 9, and a'barrel or cylinder 10 disposed between the castings 8 and 9 and having its ends closed by the castings so as to constitute a sealed unit. The shiftable shaft 2 carries a keyed pinion gear 11 which is adapted for engagement with the starter gear of the internal combustion engine being started.

The inner end of the spring 4 is secured by a stud 15 to a sleeve 12 that is journalled within the frame 1 about the shaft 2. The spring 4 and its adjacent spring 5 are oppositely wound, helical springs and their outer ends are strapped together by a helical band 16. The springs 5 and 6 are oppositely wound and their inner ends are connected by studs 17 and 18, respectively, to an arbor 13 journalled about the sleeve 12.

The outer ends of the helical springs 6 and 7, which are also oppositely wound, are strapped together by a helical band 19 similar to the band 16, and the inner end of the spring 17 is connected by a stud 20 to an arbor 14 journalled on the sleeve 12 adjacent the arbor 13.

The springs 47 are thus connected in series with each helical spring being wound oppositely with respect to its neighbors. The springs thus contact simultaneously upon relative movement between the sleeve 12 and the arbon 14. As a result, the torque available upon winding the springs is equal to the torque exerted by each spring considered individually, and the turns available is the sum of the turns stored in each one of the springs.

To control unwinding of the springs, spring expansion is limited by four retaining caps or cups 21, 22, 23 and 24. The cup 21 is fixed to the sleeve 12 so that its peripheral flange portion contains the springs 4. The cups 22 and 23 are secured to each other, back-to-back, and float on the arbor 13 between the springs 5 and 6 so that their peripheral flange portions contain these springs. The cups 24 is rigidly secured to the arbor 14 and its peripheral flange portion surrounds and contains the spring 7.

The sleeve 12 is rotatably mounted within the frame 1 by a ball bearing 25 mounted in the casting 8 and a sleeve bearing 26 supported in the arbor 14. The arbor 14 and the cup 24 to which it is secured are anchored to the casting 9 by a plurality of dowel pins 9a. A sleeve bearing 30 is interposed between the shaft 2 and the sleeve 12, and the arbors 13 and 14 are freely rotatable on sleeve bearings interposed between these arbors and the outer periphery of the sleeve 12.

At its forward end, the sleeve 12 projects through the arbor 14 and is splined into a toothed disk 27 which forms a part of a releasable, one-way clutch mechanism mounted within the casting 9. At the front or outer end of the shaft 2, a rotatable push member or button 28 is secured to the shaft adjacent a hexagonal crank portion 29 formed integrally with the shaft end. The hexagonal crank portion 29 permits the shaft 2 to be conveniently turned by a wrench or similarly formed crank.

To couple the shaft 2 to the sleeve 12, a one-way sprag type clutch 31 is disposed within the casting 8 with the inner race being defined by the shaft 2 and the outer race being a tube member 31a connected by a coupling member 32 to the sleeve 12. The member 32 has an annular configuration and substantially freely surrounds the shaft 2 and is provided with lugs 32a which extend in opposite directions therefrom for engaging notches which are formed respectively in the tube member 31a and the sleeve 12. The shaft 2 is slidably supported within a ball bearing 33 adjacent the one-way clutch 31 so that the shaft may be shifted axially as well as rotated within the starter frame 1.

To urge the shaft 2 to a normal rest position, a helical compression spring 34 is disposed about the shaft with one end bearing on an abutment tube 35 that is seated against the coupling member 32 which transfers the thrust of the spring 34 to the casting 8 through the bearing 33. The other end of the spring 34 engages an annular member 36 which is seated against the shoulder formed by the crank portion 29. The spring 34 thus urges the shaft 2 to the right in FIG. 1 to a rest position wherein the crank portion 29 protrudes from the casting 9 and is easily accessible.

The releasable, one-way clutch mechanism mounted within the casting 9 includes a roller 37 which engages the teeth of the toothed disk 27 (see also FIG. 2). A shiftable slide 38 controls the positioning of the roller 37, and the slide is urged by a compressed spring 39 to the right in FIG. 2 against a rotatable shaft 41 having a recess 43. A bell crank lever 40 is interposed between the spring 39 and the slide 38 so that the bell crank lever is spring loaded for swinging movement about a fulcrum edge 45 formed integrally with the slide 38. The slide 38 is also formed with a tooth or ledge 44 defining a pair of recesses on either side of the ledge, one of which is resiliently closed by the bell crank lever 40.

The casting 9 is releasably secured to the cylinder 10 by a plurality of dowel pins 46 so that by removing the dowel pins, the casting 9 can be withdrawn from the cylinder 10 to expose the spring power unit 3. This unit can then be slid from the cylinder 10 as a unitary cartridge made up of the sleeve 12 carrying the arbors 13, 14, the springs 4-7 and the containing cups 2124.

Referring in more detail to the bands 16 and 19, and taking the band 16 as exemplary, FIG. 5 shows the band 16 in its blank form before being rolled with the opposite ends being chamfered as indicated by the double lines. Preferably, the band is formed of a mild steel and the blank includes generally rectangular end portions 16a, 1611 which are parallel and offset by a connecting portion 160. To form the band 16, the blank is rolled to a circular section so as to define a generally helical member illustrated in elevation in FIG. 4. Holes 16d are formed in the ends of the band for use in pinning the end portions 16a, 16b to the ends of the coiled springs 4 and 5. It can thus be seen that when in assembled relation, the end portions 16a, 16b of the band 16 form continuations of the spirals of the springs 4, 5, and the portion 160 extends helically between the pair of springs. Thus, the pull from one spring to the other is in a substantially circular path that is normal to the axis of the springs and there is, therefore, little cross pull from one spring to the other. The band 19 is similarly formed and assembled with the springs 6, 7.

The operation of the starter can now be readily understood. Energy is stored by applying a wrench or suitable crank member to the crank portion 29 of the shaft 2 and rotating the shaft in a clockwise direction as seen in FIG. 2. The one-way clutch 31 locks and causes the clockwise rotation to be transmitted through the clutch 31 to the sleeve 12. This applies tension simultaneously to all of the four springs 47 since they are coupled in series and thus these springs are contracted and tensioned uniformly.

Rotation of the sleeve 12 also rotates the toothed disk 27 in a clockwise direction so that the teeth of the disk push the roller 37 from the ledge 44 of the slide 38 against the bell crank lever 40. The roller is forced down against the bias of the bell crank lever to the position shown in FIG. 7. As each tooth of the disk 27 passes over the roller 37, the bell crank lever 40 lifts the roller 37 to the position shown in FIG. 8 so that, upon relaxation of the force tending to wind the springs 47, the tensioned springs are prevented from rotating the sleeve 12 in an unwinding direction by the interposition of the roller 37 between a tooth on the disk 27 and the casting 9, the position shown in FIG. 2. Thus, the tooth disk 27, roller 37 and slide 38 act as a one-way clutch which permits rotation of the sleeve 12 only in a clockwise direction.

Because of the one-way action of the clutch 31, it will be appreciated that the shaft 2 can be oscillated by the wrench or crank applied to the crank portion 29 in order to tension or wind up the springs. With each clockwise rotation of the shaft 2, the one-way clutch 31 causes rotation of the sleeve 12 and increased tension on the springs 47. With a counterclockwise re turn movement of the shaft 2, the one-way clutch 31 permits the shaft to idly rotate within the sleeve 12 while the roller 37 locks the sleeve against unwinding movement under the force of the tensioned springs.

When the springs are fully tensioned they become coil bound and it is at once apparent to the operator that no more energy can be stored in the starter. The wrench or crank device can then he slipped from the shaft 2.

To control the application of the starting force stored in the springs 47, a release lever 42 is locked to and rotates with the shaft 41 adjacent the casting 9. The release lever is formed with an arm portion 42a (see FIG. 3) which abuts the crank portion 23 of the shaft 2 so that the shaft 41 cannot be rotated in a clockwise direction as seen in FIG. 2 until the shaft 2 is pushed within the frame 1 so as to aline an annular recess 211 on the shaft with the lever 42. Because the slide 38 is seated within the segmented recess 43 formed in the shaft 41, it will also be seen that the lever 42 and the shaft 41 cannot be rotated in a counterclockwise direction. As a result of this construction, the starter cannot be tripped and the spring energy cannot be released so long as the shaft 2 is in its rest position as shown in FIG. 1.

To utilize the starter, the operator presses the shaft 2 inwardly by exerting a force on the button 28 against the bias of the spring 34. This engages the pinion 11 with the starter gear on the engine, disposes the hexagonal crank portion 29 completely within the casting 9, and brings the recess 2a into alinement with the lever arm portion 42a. At this point, no rotating parts project from the frame 1 except the rotatable button 28.

The operator then turns the release lever 42 in a clockwise direction as seen in FIG. 2 so that its arm 42a passes through the recess 2a in the shaft 2. This causes the shaft 41, rotating clockwise in FIGS. 2 and 9, to push the slide 38 out of the recess 43. The slide 38 is thus moved to the left against the bias of the spring 39 and the ledge 44 is moved from beneath the roller 37 so that, with the parts in their FIG. 9 position, the toothed disk 27 can rotate freely in a counterclockwise direction. The springs 47 are thus released and the energy stored in the tensioned springs 4-7 is applied through the sleeve 12 and the one-way clutch 31 directly to the shaft 2. The pinion 11 thus rotates the engine starting gear so as to start the engine.

To initiate the starting operation, the shaft 2 is held in by the operator by his exerting a force on the button 28. Should the operator release the pressure on the button 28, it has been found that the force exerted through the clutch 31 by the tensioned springs locks the shaft 2 in its depressed starting position against the bias of the spring 34. This locking action exists so long as the energy stored in the coil springs 47 is transmitted to the internal combustion engine. When this energy is spent and force is not transmitted through the one-way clutch 31, the locking effect ends and the spring 34 returns the shaft 2 to its FIG. 1 position.

It will be appreciated however that in the event the shaft 2 is inadvertently held depressed so that the pinion 11 remains engaged with the engine after the engine has started, the engine will idly rotate the shaft 2 within the one-way clutch 31 so that the springs 47 are unaffected.

Following operation of the starter, the release lever 42 will be positioned so that its arm 42a lies on the opposite tensioned. The starter is thus safe to handle as a unit and can be freely removed from the engine.

To reset the starter, the lever 42 is rotated until its locked FIG. 2 position is reached. The slide 38 thus reenters the recess 43 and the springs 47 may again be Wound.

It will be appreciated that the starter disclosed herein is quite safe in operation since no rotating parts are exposed during the starting operation and also since the position of the lever 42, which controls application of force from the starter, can be readily seen at a glance. Suitable indicia can be easily applied so as to warn the user of the condition of the starter. As an important additional safety feature, the release lever 42 is positively locked when the springs 47 are tensioned so that there is no possibility of accidentally tripping the starter.

It will also be seen that a particularly compact spring power unit has been provided which is capable of exerting engine-starting torque over an appreciable interval so that the engine with which the starter is utilized can be reliably started. This result has been achieved by coupling the spiral springs 4-7 in series. As a substantial aid to assembly, replacement or servicing of the starter, the provision of the cartridge-like spring power unit 3 is of substantial significance.

Those familiar with this art will also appreciate that the exemplary starter can be economically manufactured.

I claim as my invention:

1. A starter motor for an internal combustion engine comprising, in combination, a frame, a shaft rotatably mounted in said frame, a gear on said shaft adapted to drivingly engage said engine, a sleeve rotatably mounted in said frame about said shaft, a one-way clutch coupling said shaft and said sleeve so that said sleeve can drive said shaft in one direction, a spring positioned within said frame having one end coupled to said sleeve and the other end coupled to said frame so that rotation of said shaft counter to said direction rotates said sleeve and tensions said spring, a releasable one-way clutch coupling said frame and said sleeve so that the sleeve can rotate only in said counter direction, and means for releasing said releasable one-way clutch so that said sleeve can drive said shaft under the force of said spring.

2. A starter motor for an internal combustion engine comprising, in combination, a cylindrical frame, a shaft rotatably mounted in said frame, a gear on said shaft adapted to drivingly engage said engine, a sleeve rotatably mounted in said frame about said shaft, a first spirally wound spring mounted on said sleeve with the inner end of said spring being anchored to said sleeve, an arbor coaxially and rotatably mounted on said sleeve, a second spirally wound spring mounted on said arbor adjacent said first spring and being wound oppositely thereto, the inner end of said second spring being anchored to said arbor, a helical band secured to and joining the outer ends of said first and second springs so that relative rotation beween said sleeve and said arbor contracts and tensions said springs simultaneously, a one-way clutch coupling said shaft and said sleeve so that said sleeve can drive said shaft in one direction, said arbor being coupled to said frame so that rotation of said shaft counter to said direction rotates said sleeve and tensions said springs, a releasable one-way clutch coupling said frame and said sleeve so that the sleeve can rotate only in said counter direction, and means for releasing said one-way clutch so that said sleeve can drive said shaft under the force of said tensioned springs.

3. A starter motor for an internal combustion engine comprising, in combination, a frame, a shaft rotatably mounted in said frame, a gear on said shaft adapted to drivingly engage said engine, a sleeve rotatably mounted in said frame about said shaft, a one-way clutch coupling said shaft and said sleeve so that said sleeve can drive said shaft in one direction, a spring positioned within said frame having one end coupled to said sleeve and the other end coupled to said frame so that rotation of said shaft counter to said direction rotates said sleeve and tensions said spring, a toothed disk secured to said sleeve for rotation therewith in said frame, a slide shiftably mounted adjacent the periphery of said disk, a roller interposed between said slide and said disk, said slide having a ledge which, when the slide is in a first position, holds said roller between said frame and the teeth of said disk to prevent rotation of said sleeve in said one direction, said slide having a first recess adjacent said ledge to receive said roller and permit rotation of said sleeve in said counter direction when the slide is in said first position, means for biasing said slide to said first position and said roller from said recess onto said ledge, and a release lever for shifting said slide to a second position wherein a second recess is brought adjacent said roller to free the disk for rotation in either direction.

4. A starter motor for an internal combustion engine having a starter gear comprising, in combination, a frame adapted to be coupled to said engine, a shaft rotatably and shiftably mounted in said frame, a button rotatably mounted on one end of said shaft, said shaft having a crank portion adjacent said button, means biasing said shaft to a rest position with said button and said crank portion protruding from said frame, a gear on said shaft arranged to come into meshing engagement with said starter gear when said button is pressed to move said crank portion into said frame, a sleeve rotatably mounted in said frame about said shaft, a one-way clutch coupling said shaft and said sleeve so that said sleeve can drive said shaft in one direction, a spring positioned within said frame having one end coupled to said sleeve and the other end coupled to said frame so that rotation of said shaft counter to said direction rotates said sleeve and tensions said spring, a releasable one-way clutch coupling said frame and said sleeve so that the sleeve can rotate only in said counter direction, a release lever pivoted on said frame and connected to said releasble one-way clutch so that swinging said lever from a set position disables the releasable one-way clutch, and means for locking said lever in said set position until said button is pressed to engage said gears and move said crank portion into said frame.

5. A spring power unit comprising, in combination, a cylindrical member adapted to be rotatably mounted, a first spirally wound spring mounted on said member With the inner end of said spring being anchored to said member, a sleeve coaxially and rotatably mounted on said member, a second spirally wound spring mounted on said sleeve adjacent said first spring and being wound oppositely thereto, the inner end of said second spring being anchored to said sleeve, a helical band secured to and joining the outer ends of said first and second springs so that relative rotation between said member and said sleeve contracts said springs simultaneously.

6. A spring power unit comprising, in combination, a cylindrical member adapted to be rotatably mounted, a first spirally wound spring mounted on said member with the inner end of said spring being anchored to said member, a first annular cup mounted on said member and having a flange portion containing said first spring, a sleeve coaxially and rotatably mounted on said member, a sec ond spirally wound spring mounted on said sleeve adjacent said first spring and being wound oppositely thereto, the inner end of said second spring being anchored to said sleeve, a second annular cup mounted on said sleeve and having a flange portion containing said second spring, a helical band secured to and joining the outer ends of said first and second springs so that relative rotation between said member and said sleeve contracts said springs simultaneously.

7. A releasable one-way clutch for controlling rotation between a frame and a rotatable member mounted therein comprising, in combination, a toothed disk secured to said member for rotation therewith in said frame, a slide shiftably mounted adjacent the periphery of said disk, a roller interposed between said slide and said disk, said slide having a ledge which, when the slide is in a first position,

holds said roller between said frame and the teeth of said disk to prevent rotation of said member in one direction, said slide having a first recess adjacent said ledge to receive said roller and permit rotation of said member counter to said direction when the slide is in said first position, means for biasing said slide to said first position and said roller from said recess onto said ledge, a lever for shifting said slide to a second position wherein a second recess is brought adjacent said roller to free the disk for rotation in either direction.

UNITED STATES PATENTS Jones Sept. 22, 1925 Kellogg et a1 Dec. 23, 1952 Boyce Mar. 11, 1958 Bndges Aug. 5, 1958 Danilewicz Apr. 11, 1961 FOREIGN PATENTS Great Britain Aug. 24, 1955 Great Britain Jan. 25, 1956 

1. A STARTER MOTOR FOR AN INTERNAL COMBUSTION ENGINE COMPRISING, IN COMBINATION, A FRAME, A SHAFT ROTATABLY MOUNTED IN SAID FRAME, A GEAR ON SAID SHAFT ADAPTED TO DRIVINGLY ENGAGE SAID ENGINE, A SLEEVE ROTATABLY MOUNTED IN SAID FRAME ABOUT SAID SHAFT, A ONE-WAY CLUTCH COUPLING SAID SHAFT AND SAID SLEEVE SO THAT SAID SLEEVE CAN DRIVE SAID SHAFT IN ONE DIRECTION, A SPRING POSITIONED WITHIN SAID FRAME HAVING ONE END COUPLED TO SAID SLEEVE AND THE OTHER END COUPLED TO SAID FRAME SO THAT ROTATION OF SAID SHAFT COUNTER TO SAID DIRECTION ROTATES SAID SLEEVE AND TENSIONS 